What is a T1 adjustment? Fixing a tax return you already filed
You filed your taxes and put the paperwork away. Weeks later, another document arrives. Or you open the return and notice a figure you don’t recognize. Something needs another look, but you’re not sure what.
A T1 adjustment is a request to change a personal tax return you have already filed. Think of the return as a snapshot of your tax year. A document found later may reveal a detail that was missing or recorded incorrectly.
This article covers personal tax returns outside Quebec.
Why might someone need to change a filed return?
It can start with an ordinary piece of paperwork. The difficult part is knowing whether it changes something you already filed. Consider these four situations.
A document arrived after filing
Imagine you worked a few weeks at another job last year. You have already filed when a tax slip from that employer arrives. You recognize the job, but you don’t remember seeing its income in your return.
The question is whether that income was included. The accountant compares the new slip with the return and CRA’s assessment. If the information is missing, they can explain the correction needed. If it is already there, receiving another document does not by itself mean the return needs changing.
You had the document but forgot to pass it on
A receipt stayed in your email while the rest of the paperwork went to the accountant. Perhaps you found another medical receipt in a different folder. At the time, you may not have realized it was relevant to your taxes.
CRA allows requests concerning missed income, deductions, credits or expenses. But finding a receipt does not automatically mean money is due back. The accountant checks what the document relates to, whether it can be claimed and whether it was already included.
The review answers the question behind that forgotten receipt: did leaving it out affect my return?
You noticed a number that looks wrong
Suppose you entered a figure yourself and later spotted an extra zero. Or the amount on a document does not seem to match the return someone prepared for you. You want to understand the difference before changing anything else.
A review starts with the original document and the filed information. Some amounts need correcting; others may look unfamiliar because of how they were calculated. The accountant can explain which applies and what a correction would change.
You want a second look after another accountant
The return was filed, but you left with an unanswered question. You may have remembered a document you never discussed, or you want someone to explain why the result differed from what you expected.
The review starts with your question, the return and the documents. New information may have arrived after the work was finished; the original figures may also turn out to be right. A second opinion can help you understand the result in either case.
A useful review should leave you clear about:
- what explains the difference;
- whether a correction is needed;
- what the next step would be.
Can you change a return after filing it?
Yes. First, CRA must finish assessing the original return. Its notice of assessment is the statement it sends you with the result. An adjustment request comes after that notice.
That sequence has a practical reason: CRA may already have changed a figure using information it holds. Before requesting a correction, the accountant checks what is in the return and what CRA has assessed.
The notice helps establish the starting point for the correction. For example, the figure in the copy you saved may differ from what CRA ultimately assessed. Checking both avoids requesting a change that has already been made.
You can contact an accountant while waiting for that notice. The requirement to wait applies to requesting the change, not to having a conversation about what you found.
Will I get money back—or have more to pay?
One receipt cannot tell you what your whole month’s budget looks like. In the same way, the amount on a newly found document is not necessarily the amount of a tax refund or balance. It has to be considered within the tax calculation.
For the late slip, the first useful answer is whether the income was already reported. For the forgotten receipt, it is whether the expense qualifies and was already claimed. Only then can the calculation show a possible difference.
Ask the accountant to explain what needs changing and what it may mean for your tax.
The calculation may point in either direction:
- If the tax decreases, a correction may produce a refund.
- If the tax increases, there may be more to pay.
Key idea
An adjustment request is not a promise of a refund.
What if the return is from several years ago?
It may still be possible to request a change. As checked on August 30, 2026, CRA’s Change my return service covers the previous 10 calendar years. For a request made in 2026, CRA gives 2016 or later as the example.
Older returns are not automatically impossible to change. But CRA cannot issue a refund for an adjustment requested more than 10 calendar years after the tax year ended.
For example, finding a document for 2022 in 2026 does not by itself mean you are too late. That year falls within CRA’s stated range. Whether it should change the return still depends on the document and the original calculation.
Mention the year when you contact us. If you are unsure which return it belongs to, explain what you found. We can help establish which year needs reviewing.
What can I leave with Anytime Accounting?
You can ask us to review a return you filed yourself or one prepared by another accountant. We look at the return and relevant records, explain any difference and prepare the agreed correction request. You know what is being changed before it is submitted.
For the first conversation, describe what brought you back to the return. A late document, a receipt you forgot or a number you cannot explain gives us somewhere to start. We’ll tell you which records are needed for the review.
Who handles what
Bring the question. Leave the checking and preparation with us.
You
Explain what you found
Share the question and the records you have.
Anytime Accounting
Review and prepare
Check the return, explain the changes and prepare the agreed request.
CRA
Consider the request
Review the requested changes and issue a response.
The work needs supporting records. CRA’s acceptance of the requested changes is not guaranteed.
You don’t need a finished list of corrections before calling
You may simply want someone to check whether anything was missed. The free initial consultation lets us discuss that question and the work involved. You bring your concern; the checking, explanation and preparation can be left with us.
Want help with a return you already filed?
Tell us what’s on your mind. The first consultation is free.
What clients say about working with us
Reviews from our public Google profile
Reviews on the chosen topic come first
I had a great experience with Anytime Accounting for my self-employed tax return. Olha Vozna was incredibly helpful, knowledgeable, and patient throughout the entire process. She made what can be a stressful time feel completely manageable and ensured everything was handled accurately. I felt confident every step of the way knowing I was in good hands. I highly recommend Anytime Accounting to anyone looking for reliable and professional accounting services!
On April 20, 2026, my husband and I had a tax consultation with Olga Vozna at Anytime Accounting, which we had scheduled about a month in advance given the busy tax season. From the very beginning, the experience was exceptionally well-organized and client-focused. The administrative assistant was professional, welcoming, and proactive—she provided us with all necessary intake forms ahead of time, along with clear guidance on pricing, eligible expenses, and helpful resources to prepare us for the meeting. We also appreciated the reminder call a few days prior, which reflected a high level of care and attention to detail. During the consultation, Olga took the time to walk us through the Canadian tax system in a clear and structured way, explaining both federal and provincial tax considerations. She addressed our specific situation thoughtfully, including international income reporting and my university tax credits, ensuring that we fully understood how everything would be reflected in our returns. What stood out most was the clarity and transparency. We felt informed, comfortable, and confident before signing any documents—something we had not experienced with our previous accountant, where explanations were minimal and often provided only after the fact. Anytime Accounting truly distinguishes itself through its client-oriented approach and commitment to clear communication. We are already planning to return later this year for financial planning to better prepare for the upcoming 2026 tax cycle. In short, this is a team of trusted professionals who are well worth your attention. If you are looking for thoughtful guidance, clarity, and a personalized approach, Anytime Accounting—and especially Olga Vozna—would be an excellent choice for your family’s tax needs.
FAQ
Yes. Your return includes federal and provincial or territorial income tax, and provincial rules differ. For an ordinary resident return, the relevant province is generally where you lived on December 31 of that tax year. Tell us if you moved; your current address alone does not settle the tax for a past year.
As of August 30, 2026, CRA lists 2 weeks online and 14 weeks from receipt by mail. Certain requests, including several returns or cases where CRA asks for more information, may take up to 36 weeks. These are processing standards, not a guaranteed date.
Not necessarily. CRA may accept all, some or none. It issues a notice of reassessment for changes made and explains requested changes it did not make.
Official Canadian sources (5)
CRA sources checked on August 30, 2026. This article covers personal returns outside Quebec.
This article is general information, not personal tax advice. Your situation may differ. For advice specific to you, book a free call.